How to Plane Rough Lumber

Learn the basics of flattening rough-sawn wood

Expand your woodworking skills and get access to a wide range of domestic and imported wood for your furniture projects by learning to flatten and plane rough-sawn lumber.

By the DIY experts of The Family Handyman Magazine:May 2011

The flattening process

1 of 6

Photo 1: Lay out the parts

Use chalk to lay out the parts
you expect to get out of the
board. Work around knots,
cracks and edges with deep
tree bark. If there are several
parts coming from the same
board, draw yourself a paper
sketch to remind you of the
layout. Then cut the board to
lengths corresponding to the
parts. Cut each part at least 2
in. longer than the final length.
Do so even if knots, checks or
cracks are part of the waste at
the ends. That’ll allow you to
remove any checks on the ends
of the boards or snipe (gouges)
left over from the planer. Don’t
work with long boards unless
they’re called for; it’s much
easier to flatten short boards.

2 of 6

Photo 2: Flatten one side

First, sight down the board to find out if there’s a bow. Set the jointer depth at 1/32 in. or
so and push the board through the knives with the bowed side up. You’ll hear the knives
cutting off the high spots as you push it through. Don’t worry about holding it tight
against the fence. Keep most of the downward pressure on the board over the infeed
bed of the jointer, with little or no pressure on the outfeed side. Keep making passes
until the entire board is flat. When you’re making the last couple of passes, apply a bit
more pressure on the outfeed side.

3 of 6

Photo 3: Flatten the opposite side

Send the highest point (at either end) of the board through the planer first, with a very
small cut. Sneak up on the cutting depth; there are likely to be high spots that might
stall the planer as they come through the knives. After the first pass, you can cut a bit
deeper, but shallower passes will be less taxing on the tool and less likely to produce
tear-out, stalls and burning. As with the jointer, swing the board around and send the
other end through if you get any tear-out. Before you get to the final thickness, plane
out any tear-out on the first side.

4 of 6

Photo 4: Flatten one edge

Sight the board to find any bows. Hold the board against the fence with the bowed
side up and send it through the jointer just as you did for the sides. Stop when the
edge is flat.

5 of 6

Photo 5: Rip away the waste

Place the jointed edge against the table saw fence and rip the board to within 1/8 in. of the final width.

6 of 6

Photo 6: Joint either edge to the final width

If the board is 1-1/2 in. or thicker, you
can use the planer for this step. Or if
you have several thinner boards of the
same thickness, you can “gang-plane”
them all at once. Hold the boards
together as they enter and exit the
planer. Cut the boards to final length
and you’re ready to start your project!

If you’re an aspiring woodworker who
wishes to move on to more advanced
projects, there’s only one path. That’s
learning how to flatten rough-sawn
wood. Continuing to buy S4S (smooth
all four sides) at the home center will
limit your project portfolio for two reasons.
First, you’re stuck with 3/4-in.-thick stock. Advanced woodworking
calls for a myriad of thicknesses only
available in rough-sawn form. Second,
by flattening dry, rough-sawn wood,
you’ll end up with boards that are perfectly
flat, straight and true, which is
rare with store-bought boards.

It takes an investment to flatten wood,
though. You can’t pull this off without
a jointer, surface planer and table saw.
You could spend a ton of money on
a jointer, but a basic 6-in. jointer will
do most everything you’ll need; prices
start at about $400. If you’re only doing
small projects, you can get away with
a 4-in. jointer for less money, but you
won’t be able to flatten wider boards.
Surface planers start at about $350. But
you won’t get good results with either
tool unless you keep them equipped
with sharp knives. As for the table
saw, any type will work fine, including
portables.

Woodworkers all have their own
system for flattening wood, some of
which are pretty complex. This is one
simple method that’ll get you started.
As you get comfortable with flattening,
you’re sure to develop your own.

Jointer

Jointer Smarts

Be persnickety and square the fence to the bed
before any jointing. That’s the only way to ensure
square sides.

A rust-free polished bed and fence will give you
much better results.

When you’re jointing edges, move the fence every
dozen or so passes to spread the wear over the
entire edge of each knife.

From rough-sawn to flat, straight and true

1 of 6

Rough-sawn wood

Rough-sawn wood is at least 1/4-in. thicker than equivalent S4S wood from the home center, allowing you to flatten and straighten it. It’s also cheaper.

2 of 6

Joint one side

Send it through
the jointer with the
bowed side up.

3 of 6

Plane opposite side

Send it through
the planer with the
freshly jointed side
down.

4 of 6

Joint one edge

Joint with the
bowed edge up.

5 of 6

Rip to rough width

Rip 1/8 in. wider
than finished width.

6 of 6

Joint to final width

Finding Rough-Sawn Lumber

If you have a hardwood retailer or woodworking supplier near
you, that’s great. If not, you can shop
online. Many rural woodworkers,
including
pros, buy
all their
wood online.
Search for
“hardwood
suppliers” to find many sources.

Board thicknesses are always
listed as “X/4.” A 4/4 board is 4 by
1/4 in., or 1 in. Always get 1/4 in.
thicker than the finished thickness
you’re after. For example, if you
need a 1-in.-thick final thickness,
you should order a 5/4 board. Select
widths that are 1/2 in. or so wider
than the finished width.

Dealing with tear-out

1 of 1

Tear-out

Chatter and tear-out happens when the grain direction slopes up into the planer blades rather than away from them. Some woods are more prone to the problem than others; changing feed direction and setting the jointer or planer as shallow as possible will usually help.

If you have tear-out or chatter during jointing, swing the board around and send the other end through first. If the tear-out is still there after the side is flat, let it go and send that side through the planer after the other side has been flattened.The planer gives a smoother cut than the jointer. If that doesn’t do it, you’ll just have to sand your way out of the jam.